Cooling system for aeronautical engines



Dani, 1933. w. F. DAVIS 1,938,537

COOLING SYSTEM FOR AERONAUTICAL ENGINES Filed March 29, 1932 Main 5 N ATTORNEY Patented Dec. 5, 1933 UNITED STATES PATENT" OFFICE I COOLING SYSTEM FOR AERONAUTICAL ENGINES This invention relates to engine cooling systems' and particularly to a system for cooling high speed, high powered aeronautical engines.

In accordance with my invention I provide'a 5 plurality of nozzle-like casings in the bottom of an engine cowling, with .the ends of exhaust pipes projecting into the casings and forming an ejector.' By virtue of this ejector arrangement, air admitted to the cowling through 1Q frontal openings therein is caused to traverse the cylinders of the engine by suction created at the ejectors by the kinetic energy of the exhaust gases. This air is ejected from the cowling through the nozzle-like casings whereby a conand low pressure conditions within the cowling are insured.

An object of the invention is to provide an air cooling system for a multi-cylindered aeronautical engine.

Another object of the-invention is to provide in an air cooling system for an engine provided with a cowling and an air inlet, a positively acting air ejector.

These and other objects will be apparent to those skilled in this particular art from the claims and descriptions in the specification in I connection with the drawing, in which:

Figure 1 is a front elevation of an airplane engine enclosed by a cowling; I

Figure 2 is a side elevation of Figure 1; and

Figure 3 is a flow diagram of cooling air admitted to the cowling illustrated in Figures 1 and 2.

In the embodiment of the invention which has been chosen for the purpose of illustration and referring now tothe drawing, I have shown an aeronautical engine 10 enclosed by a cowling 11. The engine 10 is shown as being of the inverted V type, and has two banks of cylinders 12 and 14 that may be suitably finned. and provided with baiiles of the type illustrated and claimed in my two copending applications; No. 581,851 and No. 581,852, filed December 18, 1931.

The cowling 11 is provided with two suitably shaped apertures 15 and 16 located to the side of and. slightly below a spinner 17. By virtue of the shape of the spinner and the nature of the apertures, air admitted to .the cowling through these apertures, when the airplane is in motion, will be deflected downward and flow towards. the rear of the cowling in a space provided between the cylinders 12 and 14 and the sides of the cowling. Due to the shape of the cylinders, the efiect of the bailing associated vdistance in' each of these casings.

stant supply of cold air traversing the cylinders therewith and of a suction created in the space between the cylinders, the air admitted through the apertures 15'and 16 sweeps around the cylinder walls and absorbs heat therefrom. Two rows of nozzle-like air outlet casings 20 are provided in the bottom of the cowling 11 and the ends of exhaust pipes 21 project a short This arrangement of outlets associated with exhaust pipes provide eifective ejectors, which, when the engine is in operation, create, due to the kinetic energy of the exhaust gases, a suction which insures low pressure conditions within the space between the two banks of cylinders 12 and 14. This low pressure condition created in the space between cylinder banks causes the air admitted to the space between the outside of the cylinders and. the sides of the cowling to rush to the space between the two banks of cylinders, and hence insures low pressure conditions within the cowling and a positive flow of cooling air across the heated surfaces of the cylinders. A suitable opening may be provided in the cowling at the bottom and to the rear to permit the escape of heated airnot sucked through the ejectors 20 to -destroy any air pressure built up inside the ship cowling not taken care of by the ejectors.

The engine cooling system just described in detail provides numerous advantages. For example, speed of the airplane is increased due 7 to the absence of pressure inside the cowling for, by virtue of the positive ejectors, heated air is removed from the cowling at a speed such that the building up of any substantial air pressure is prevented. The frontal appearance of gine enclosure is provided.

In additionto the foregoing, by providing a positive removal of air from within .the cowling a greater amount of cooled air is admitted thereto at a high velocity and this air is caused to sweep around the heated walls of the cylinders and hence has a maximum cooling'eflect.

A specific system has been described in some detail but it ls-to be understood that changes, additions, substitutions and omissions may be made therein within the spirit of the invention as defined by the appended claims.

I claim: 1. In an air coolingsystem for a multi cylindered aeronautical engine of the inverted V- type, a streamlined cowling enclosing saiden-' gine and having a frontal aperture, air outlets disposed in said cowling between the banks of cylinders of the inverted V-engine, said apertures cooperating with exhaust pipes from said engine to form ejector nozzles whereby air admitted by said apertures is drawn around the cylinders in contact therewith and ejected from the cowling through said air outlets.

2. In an air cooling system for a multi-cylinder aeronautical engine, a streamlined cowling enclosing said engine and having frontal apertures, a plurality of air outlet pipes extending from said cowling in-line and in staggered relation, which co-operate with the exhaust pipes from said engine to form ejector nozzles whereby air admitted by said apertures and which has contacted said cylinders is ejected from said cowling.

3. In an air cooling system for a multi-cylinder aeronautical engine of the inverted V-type, a streamlined cowling enclosing said engine and having a pair of frontal apertures, a plurality of outlet pipes extending in staggered relation in two separate lines from said cowling between the banks of cylinders of the inverted V engine, each of said pipes surrounding the discharge end of an exhaust pipe from said engine and having its inner end enlarged to form ejector nozzles whereby air admitted by said apertures is drawn around the cylinders in contact therewith and ejected from the cowling through said air outlet pipes.

4. In a system for air cooling internal combustion engines, a streamlined cowling enclosing said engine and having a frontal aperture, outlet pipes extending from said cowling, each of said pipes surrounding the discharge end of an exhaust pipe from said engine to form ejector nozzles whereby the air admitted by said aperture is ejected from said cowling.

WALTER F. DAVIS. 

